Automatically Delete images in the library older than a certain amount of time

Users are not good at cleaning up after themselves. Some of our users have thousands upon thousands of snag files taking up space, that date back over a year. We would like to implement a systematic way to clear these on a timely basis (for example, all older than 30 days would be deleted). While we can script the removal of the snag files, this would cause broken thumbnail images in the user library, as that file and it's metadata would still be listed in the snag900.sdf database. We'd like to see an option added that, upon open or close, would delete items older than XX days.